Connector for blood pumps and the like



Nov. 12, 1968 R. T. JONES 3,409,9i4

CONNECTOR FOR BLOOD PUMPS AND THE LIKE Filed July 1. 1966 2 Sheets-Sheet 1 37 I5 32 33 5" V w ILQA O 43 ROBERT T. JONES INVENTOR. J 1E mum ATTORNEYS Nov. 12, 1968 JONES 3,409,914

CONNECTOR FOR BLOOD PUMPS AND THE LIKE Filed July 1. 1966 2 Sheets-$heet 2 400 FLOW J ROBERT mom-:3

INVENTOR.

BYMQ/iv 0 "Mm film ATTORNEYS United States Patent 0 M 3,409,914 CONNECTOR FOR BLOOD PUMPS AND THE LIKE Robert T. Jones, Lexington, Mass., assignor to Avco Corporation, Cincinnati, Ohio, a corporation of Delaware Filed July 1, 1966, Ser. No. 562,199

5 Claims. (Cl. 31)

This invention relates to blood pumps and the like and more particularly to means for connecting arterial graft sections to implantable blood pumps and the like.

The adventof openheart surgery has presented to the medical profession the opportunity of repairing damaged or diseased hearts of individuals and where appropriate using circulatory assist systems in individuals who with out such correction and/ or systems face premature deatn. Many devices are involved in this type of surgeryLFor example, one circulatory assist system may comprise an auxiliary ventricle or valveless blood pump connected across the arch of the arota and driven by fluids pressure in response to electronic signals (QRS wave) provided by the heart itself. By operating the auxiliary ventricle in proper phase, the systolic pressure in the left heart can be reduced and thesystemic circulation can be maintained with a substantially reduced work load on the heart muscle. In addition, the operation of the auxiliary ventricle has the effect of shifting the phase of the normal systolic pressure so that this pressure app'ea'rs in the aorta at a time when the left ventricle is relaxed. Assuming competence of the normal aortic valve, one then has an increased perfusion pressure available to the coronary arteries. It is believed that such an increase in coronary perfusion, together with a reduction in the effort required from the heart, should be effective in a number of cases of cardiac insufficiency;

As may be seen from the above, one important component of circulatory assist systems is a pump that either assumes the hearts role of pumping blood or which reduces'the work load of the heart muscle. By using heart pump equipment for extended periods of time, it is con-' templated that the equipment may be utilized for regional perfusions in therapeutic treatment of the heart. Still other use ofthe equipment will be to provide circulation of blood through an artificial organ such as an artificial kidney. In connection with this function of the apparatus, it should be noted that many research institutions at this time are concentrating the research activities on pro viding artificial counterparts of other organs, and whenever such application requires circulation, the present invention may be utilized.

Implantable prior art pulsatile pumps usually consist of a flexible bulb or ventricle squeezed by pressurized fluids and coupled to one or more blood vessels such as arteries or veins. Generally, arterial graft sections connect the bulb to the circulatory system. These arterial graft sections are generally of the woven Teflon-type or Dacron-type employed in the insertion of arterial grafts and the replacement of damaged sections of an artery.

Heretofore, in such prior art pumps, the manner in which the arterial graft sections were attached to the bulb resulted, among other things, in unsatisfactory growth of tissue at the junction of the graft material and the bulb. By unsatisfactory growth of tissue is meant growth in such a manner as to result in free forming clots or clots which break off and are carried away by the blood stream. Accordingly, a feature of the present invention is the provision of a connector in an implantable prosthetic device connected to the circulatory system which has improved clotting characteristics.

Another feature of the present invention is the provision in an auxiliary ventricle or the like of connectors 3,409,914 Patented Nov. 12, 1968 which tend to prevent unsatisfactory tissue growth at the junction of arterial graft sections and that portion of the auxiliary ventricle or the like on which tissue will not grow.

A further feature of the present invention is the provi' sion in an auxiliary ventricle or the like of a connector at the inlet end which decreases in diameter at the junction of an arterial graft section and-the ventricle.

A still further feature of the present invention is the provision in an auxiliary ventricle or the like of a connector at the inlet end which provides a decrease in diameter at the junction of an arterial graft section and the ventricle and a connector at the outlet end which provides a substantially constant diameter.

The novel features that are considered characteristic of the present invention are set forth in the appended claims; the invention itself, however, both as to its organization and method of operation together with additional objects and advantages thereof, will best be understood from the description of a specific embodiment when read in conjunction with the accompanying drawings, in which:

FIGURE 1 is a perspective ,view with parts broken away of an implantible auxiliary ventricle incorporating the present invention;

FIGURE 2 is a side view with parts broken away of a connector in accordance with the present invention adapted for use at the outlet end;

FIGURE 3 is an end view taken on line 3-3 of FIG- URE 2; and

FIGURE 4 is a partial sectional view of a connector essentially the same as that shown in FIGURE 2, but adapted for use at the inlet'end.

Directing attention now to FIGURE 1, there is shown by way of "example a valveless auxiliary ventricle generally designated by the numeral 10, incorporating the present invention. While the present invention will, for convenience, be described in connection with an implantable auxiliary ventricle, it is to be understood that it may be used in conjunction with prosthetic devices, plastic tubes and the like, adapted for connection to the circulatory system over extended if not indefinite periods of time.

The auxiliary ventricle as shown in FIGURE 1 is adapted for implantation within a living body. Arterial graft sections 11 and 12 are attached to the open ends of the auxiliary ventricle by connector means fully described hereinafter. For the type of auxiliary ventricle shown, the arterial graft sections 11 and 12 generally are surgically attached to the aorta (not shown) in conventional manner. The arterial graft sections may be of thewell known WOV6I1 Teflon-type employed in the insertion of arterial grafts and the replacement of damaged sections of an artery. Edwards Seamless Arterial Graft manufactured by the United States Catheter and Instrument Company have been found to be satisfactory.

The auxiliary ventricle is comprised of an elongated and compliant bulb 13 having an inlet opening 14 and an outlet opening 15 to permit blood to freely flow therethrough. The aforementioned arterial graft sections are attached to the auxiliary ventricle at these openings. The

bulb may be comprised of a flexible material acceptable to the blood, such as for example Medical Silastic 372 supplied by Dow Corning Corporation, Midland, Mich. The bulb may have a generally ellipsoidal configuration or alternately have a generally U-shaped configuration as shown in FIGURE 1. The bulb has a capacity sufficient to receive an appreciable fraction of the outflow from the left ventricle of the heart and is shaped to provide optimum fiow conditions and minimum stresses during use.

Surrounding and sealably connected to the bulb 13 at i p 3 I its open ends is a rigid and air tight case 16 including a pressure conduit 17 couple thereto for transmitting pulses of a fluid or a gas, such as for example oxygen, to the region between the bulb 13 and the case 16. Inlet connector means and-outlet'connector means generally designated respectively by the numerals21 and 22 attach the arterial graft sections to the auxiliary ventricle. Suitable connectormeans incorporating the present invention now to be described in detail attaches the arterial graft-sections to the auxiliary ventricle in sucha manner as to at least reduce if not eliminatepost operative clotting and unsatisfactory growth of tissue at the inlet and outle ends of the auxiliary ventricle.

Directing attention now to FIGURES 2 and 3, there is shown connector 22 in accordance with a preferred embodiment of the present invention intended for use at the outlet end of the auxiliary ventricle comprising a rigid hollow cylindrical inner member 31 sealably' attached as by bonding it to the portion of the case 16 surrounding opening in the bulb 13. The extremeend 32-of the inner member 31 remote from the case 16 is provided with a continuous smooth curved end surface 33 preferably in the form of an outwardly extending lip 34 and intermediate its end portions, the inner member 31 is also provided with an outwardly projecting annular ring 35 threaded to receive a rigid cylindrical outer member 36 more fully described hereinafter. The portion ofthe bulb defining opening 15 extends through the inner member 31 and over, around and past the aforementioned curved end surface 33 to form a cuff 37 is preferably sealably attached to the outer surface of the inner member by both a suitable adhesive and by wrapping and tying it with thread 38 such as Dacron thread or the like adjacent threaded ring 35.

The provision of the cuff 37 formed by the end portion of the bulb disposed over continuously curved end surface 33 is particularly advantageous in that it minimizes if not essentially eliminates the possibility of failure of the bulb as by fatigue at or adjacent its junction with the case and/ or inner member 31.

=Disposed over the cuff 37 former by the end portion of the bulb is arterial graft section .12 which is preferably also tied and bonded to the cuff adjacent threaded ring 35. Directing attention now to the cylindrical outer member 36, it will be noted that it surrounds inner member 31 and is adapted for threaded engagement .with threaded ring 35 to facilitate assembly of the connector. Integral with that portion of the outer member 36 remote from the case 16 is an inwardly-extending ring-like member 41 theradial dimension of which is sufficient to extend in- 'wardly over lip 34 and permit a cloth-like filler material 42 having a large number of interstices of a size to promote clotting, such as for example a short piece of arterial graft section having a diameter slightly greater than that of graft section '12 and comprising several radially disposed layers, to be gripped between ring 41 and cuff 37. The provision of absorbent material 42 behind the arterial graft section is important in that it permits blood to enter the interstices or pores and by clotting there to permit proper ingrowth of tissue.

It is particularly important to note that as shown in FIG- URE 2 for a connector intended for use at the outlet end, the radial dimensions of lip 41 are sufficient to provide a more or less continuous cylindrical passage comprising inner surface 40 of the bulb in inner member 31 and the arterial graft section 12. It is important to note that the diameter of surface 40 is substantially the same as the effective inside diameter of graft section 12, i.e., there is no substantial change in diameter as one moves from thhe surface 40 to graft section 12 exterior of the auxiliary ventricle. Whereas this is not deemed desirable for the connector at the inlet end, it is desirable at the outlet end as it prevents flow separation and is conducive to even growth of tissue beginningat the junction of cuff 37 and graft section 12.

A plurality of openings 43 are provided in the outer member 36 adjacent ring 41-to permit blood to pass from the interior of the arterial graft section to and through the filler material 42 at the junction of the arterial graft section 12 and cuff 37.1 f I The inner 'and outer members 31 and 36"may be composed of surgically implantable stainless steel, such asfor example 303'or 316 stainless steel, dipped in silicone resin prior to assembly to providea coating of about /2 to 1 nil in thickness.

After the arterial graft section 12 has been attached to inner member 31, the filler material 42 preferably comprising several layers is.disposed within the outer member at ring 41. Theouteranember 36 is then slipped over the arterial graft section and threaded onto the inner member 31 to compress the filler material 42 to a point where substantially maximum contact is. provided'between the filler material 42, ring 41 and that portion of thearterial graft'section 12 covering the extreme end of cuff 37. A suitable adhesive 44, such asSilastic, may be provided at threaded ring to provideaseal at this pointand to hold ring 36. in place. A high compression connection is neither necessary nor desirable as it will result in excessive restriction of blood flow in and through the filler material and any tissue which subsequently forms in this region. While the number and type of openings 43 provided in Outer member 36 is not critical, it is recommended that atleast a substantial portion of the outer periphery of the filler material 42 be exposed to permit maximum perfusion of blood through the tissue which subsequently for-ms inand around the filler material .42. a I

Attention is now directed to FIGURE 4 which shows connector 21 intended for use at the inlet end of the auxiliary ventricle. The connector as shown in FIGURE 4 is essentially the same as that shown in FIGURE 2 with the exception that it is arrangedand adapted to provide a decreasing diameter as one moves in-the direction of flow from the graft section 11 just exterior of ring 410 to that portion of the bulb disposed within inner member 31 and rearwardly of end surface 33. The aforementioned decrease in diameter may be simply and inexpensively provided by increasing the inner diameter of ring 41 as shown in FIGURE 2 by a small amount, such as for example about 2 millimeters. Thus, if ring 41 for an outlet connector as shown in FIGURE 2 is provided, with an inner diameter of about 20 millimeters, the inner diameter of ring 41a as shown in FIGURE 4 may be provided with an inner diameter of about 22 millimeters. The diameters of surfaces 40 and 40a maybe the same. These dimers, sions will of course vary for different patients.

It will now be apparent that a decrease in diameter is provided in the inlet connector at the junction of the graft section 11 and cuff 37. As tissue grows in this region,

it 'will tend to form a regular surface having a constantly decreasing diameter in the direction of flow. This decrease in diameter increases the flow velocity and provides a washing action at cuff 37 thereby at least reducing the possibility of unsatisfactory clotting and/ or tissue growth.

As noted previously, it is believed that a change in diameter and particularly an increase in diameter in the direction of flow beginning at cuff 37 in the outlet connector 22 is to be avoided.

Having described a preferred embodiment of the invention, what is claimed is:

1. In apparatus for receiving blood from a blood vessel such as an artery or vein in a living body and having a smooth inner surface exposed to andacceptable to said blood and on which clots and tissue will not form, said surface defining a cylindrical inlet opening an a cylindrical outlet opening, the combination comprising:

(a) a first arterial graft'section having an effective diameter greater than that of said inlet opening; and

(b) first substantially cylindrical connector means for maintaining arterial graft section in contact with said surface defining said inlet opening, said connector means substantially maintaining the said effective diameter of said graft material up to its point of contact with said surface whereby the velocity of said blood adjacent said inner surface of said graft section is increased at said point of contact, said connector means being provided with a plurality of openings adjacent the junction of said surface and said graft section; and first perforate means having a large number of interstices of a size to promote clotting disposed within said connector means adjacent said junction and in communication with said openings and said graft section.

2. The combination as defined in claim 1 wherein said surface defining said inlet opening is supported by said connector means to provide a constantly decreasing diameter in the direction of flow adjacent said junction of said surface and said graft section and a constant diameter remote from said junction.

3. The combination as defined in claim 2 and additionally including:

(a) a second graft section having an effective diameter substantially equal to that of said outlet opening; and

(b) second substantially cylindrical connector means for connecting said second graft section to said surface defining said outlet opening whereby the diameter of at least a majority of said outlet opening and the diameter of said second graft section are substantially the same adjacent their point of contact.

4. The combination as defined in claim 1 and additionally including:

(a) a second graft section having an effective diameter substantially equal to that of said outlet opening; and

(b) second substantially cylindrical connector means for connecting said second graft section to said surface defining said outlet opening whereby the diameter of at least a majority of said outlet opening and the diameter of said second graft section are substantially the same adjacent their point of contact.

5. The combination as defined in claim 4 wherein said second connector means is provided with a plurality of openings adjacent the junction of said surface defining said outlet opening and said second graft section; and second perforate means having a large number of interstices of a size to promote clotting are disposed in said second connector means adjacent said junction and in communication with said openings in said second connector means and said second graft section.

References Cited UNITED STATES PATENTS 2,978,262 4/1961 Franck 285248 3,007,416 11/1961 Childs 10344 3,097,366 7/1963 Winchell 31 3,152,340 10/1964 Fry et al. 31 3,208,757 9/ 1965 Iaqeman 285260 XR 3,357,432 12/1967 Sparks 128334 3,380,764 4/ 1968 Wilson 285249 FOREIGN PATENTS 117,043 5/ 1943 Australia.

OTHER REFERENCES RICHARD A. GAUDET, Primary Examiner.

RONALD L. FMNKS, Assistant Examiner. 

1. IN APPARATUS FOR RECEIVING BLOOD FROM A BLOOD VESSEL SUCH AS AN ARTERY OR VEIN IN A LIVING BODY AND HAVING A SMOOTH INNER SURFACE EXPOSED TO AND ACCEPTABLE TO SAID BLOOD AND ON WHICH CLOTS AND TISSUE WILL NOT FORM, SAID SURFACE DEFINING A CYLINDRICAL INLET OPENING AN A CYLINDRICAL OUTLET OPENING, THE COMBINATION COMPRISING: (A) A FIRST AERTERIAL GRAFT SECTION HAVING AN EFFECTIVE DIAMETER GREATER THAN THAT OF SAID INLET OPENING; AND (B) FIRST SUBSTANTIALLY CYLINDRICAL CONNECTOR MEANS FOR MAINTAINING ARTERIAL GRAFT SECTION IN CONTACT WITH SAID SURFACE DEFINING SAID INLET OPENING, SAID CONNECTOR MEANS SUBSTANTIALLY MAINTAINING THE SAID EFFECTIVE DIAMETER OF SAID GRAFT MATERIAL UP TO ITS POINT OF CONTACT WITH SAID SURFACE WHEREBY THE VELOCITY OF SAID BLOOD ADJACENT SAID INNER SURFACE OF SAID GRAFT SECTION IS INCREASED AT SAID POINT OF CONTACT, SAID CONNECTOR MEANS BEING PROVIDED WITH A PLURALITY OF OPENINGS ADJACENT THE JUNCTION OF SAID SURFACE AND SAID GRAFT SECTION; AND FIRST PERFORATE MEANS HAVING A LARGE NUMBER OF INTERSTICES OF A SIZE TO PROMOTE CLOTTING DISPOSED WITHIN SAID CONNECTOR MEANS ADJACENT SAID JUNCTION AND IN COMMUNICATION WITH SAID OPENINGS AND SAID GRAFT SECTION. 